Anyone else have problems opening the back doors?

I just received a 1997 jeep cherokee sport, and the back doors won't open, or even unlock. I've replaced the necessary fuses, and I still have no idea. Any help will be greatly appreciated. Thanks!

What happens when you press the manual lock/unlock button on the door? Does it "resist" or does it easily flip back and forth?

It doesn't just resist, it will not unlock. I guess tonight I will have to figure out how to take the doors apart, from the inside, without hurting anything, and there's only three screws showing.